塔里木盆地周缘南华系底界探讨

Discussion on the Bottom Boundary of the Nanhua System in thePeriphery of Tarim Basin

塔里木盆地周缘广泛发育新元古代冰碛岩沉积,关于南华系底界及其年龄的认识仍在不断更新。基于地层划分方案、冰碛岩沉积时代、冰川沉积特征与环境,对冰期事件进行对比分析,明确了塔里木盆地阿勒通沟冰期(库鲁克塔格地区)、巧恩布拉克冰期(阿克苏地区)和波龙冰期(叶城地区)与国际上Sturtian冰期之间存在的对应关系。建议将塔里木盆地南华系底界向上调整为上述冰期沉积的底界,将底界年龄修订为720 Ma。

Neoproterozoic moraine deposits are widely developed in the periphery of Tarim Basin,and the understanding of the Nanhua system bottom boundary and its age is still constantly updated.Based on stratigraphic division scheme,diamictite sedimentary age,glacial sedimentary characteristics and environment,comparative analysis of glaciations has been carried out.It is clear that the Altungol glaciation(Quruqtagh area),Qiaoenbrak glaciation(Aksu area),Bolong glaciation(Yecheng area)correspond to the Sturtian glaciation(global).It is suggested that the bottom boundary of the Nanhua System in the Tarim Basin should be adjusted upward to the bottom boundary of the above glacial deposition,and the age of the bottom boundary should be revised to 720 Ma.